The present invention relates generally to composite tube assemblies and more particularly to composite tube assemblies having form locking or fittings.
Carbon composite offers high stiffness and/or strength-to-weight ratios. Composite tube assemblies are used for transferring loads in structures such as aircraft or spacecraft. Other applications include control rods, containers, ducts, panel inserts, torque tubes, etc.
In vehicles such as an aircraft, it is beneficial to use the composite tube assemblies rather than assemblies primarily composed of metal. The composite tube assemblies are lighter in weight, more resistant to corrosion, stronger and more inert relative to substantially metallic assemblies. Composite tube assemblies may be used in an overhead luggage bin (or stow bin) assemblies in an aircraft to provide structural support both when the bin is in an open configuration and when it is closed. The composite tube assemblies may also facilitate installation of the stow bin in the aircraft. The composite tube assemblies may also be used as structural members in vehicle frames.
When a tube composed of carbon composite is connected to a push-pull load a metallic end fitting and/or a tubular insert is often used as a connector between the tube and the push-pull load. However, carbon composite may have a rate of thermal expansion and/or negative thermal expansion (i.e. contraction) substantially different from that of the metallic end fitting. Such a difference in the rate of thermal expansion and/or contraction can stress a connection between the tube and the metallic end fitting and progressively weaken the connection over time. Consequently, a robust connection between a composite tube and a fitting is desired.